Multidose disposable syringe and method of filling same

Abstract

The multidose syringe is provided with two pistons which are attached by a string to move simultaneously. A groove in the barrel for delivering fluid into and from the innermost fluid chamber is provided with baffles to create turbulence in the fluid flow to preclude entry of air into the fluid chamber between the pistons during filling of the syringe.

What is claimed is: 
     
       1. A multidose syringe comprising a one piece cylindrical barrel having an open end and a tip defining a closed end with a duct extending therefrom;   a first piston mounted in said barrel in friction-fit relation to move from a first position abutting said closed end to a second position spaced therefrom to define a first chamber therebetween for receiving a first fluid;   a second piston slidably mounted in said barrel in friction-fit relation to move between a first position adjacent said first piston and a second position spaced therefrom to define a second chamber therebetween for receiving a second fluid;   a piston rod connected to said second piston and extending from said barrel;   collapsible means connecting said pistons to move said first piston with said second piston after predetermined movement of said second piston from said first piston after filling of said second chamber with a fluid;   a passageway disposed between said first piston and said barrel defining a communicating path between said duct and a point between said pistons with said first piston in said first position thereof; and   means in said passageway to create turbulence in a flow of fluid drawn into said second chamber to preclude an air flow into said second chamber.   
     
     
       2. A multidose syringe as set forth in claim 1 wherein said passageway is disposed in said barrel. 
     
     
       3. A multidose syringe as set forth in claim 1 wherein said tip includes means for attaching a catheter tube about said duct. 
     
     
       4. A multidose syringe as set forth in claim 1 wherein said tip includes a concical end wall and said first piston has a plurality of protoberances thereon for abutting against said end wall in said first position thereof. 
     
     
       5. A multidose syringe as set forth in claim 1 where said means in said passageway includes a plurality of parallel longitudinally disposed baffles. 
     
     
       6. A multidose syringe comprising a barrel having an open end and a tip defining a duct at an opposite end;   a piston rod disposed within and extending from said barrel;   a first piston connected to said piston rod and slidably mounted in said barrel in friction-fit relation;   at least a second piston mounted in said barrel between said first piston and said duct to move between a first position abutting said tip and a second position spaced from said tip to define a chamber therebetween to receive a fluid;   a groove in said barrel defining a communicating path between said duct and a point between said pistons with said second piston abutting said tip in said first position; and   collapsible means connecting said second piston to said first piston to move said second piston with said first piston after a predetermined movement of said first piston from said tip.   
     
     
       7. A multidose syringe as set forth in claim 6 wherein said collapsible means is a string secured to and between said pistons. 
     
     
       8. A multidose syringe as set forth in claim 7 wherein said string is secured to said second piston and slidably disposed in said first position. 
     
     
       9. A multidose syringe as set forth in claim 8 which further comprises a plurality of spaced apart stops on a free end of said strings, a flange on said piston rod and a slot in said flange slidably receiving said string with a selected one of said stops abutting said flange.